The present invention relates to a multiprocessor system including firmware.
A central processing unit (CPU) of a data processing system generally fetches instructions sequentially from a main memory and then executes them sequentially. There are a variety of instructions, some of which, such as system control instructions, extended instructions, and instructions for emulating another processing unit, make the processing operations very complicated.
To simplify processing operations complicated due to such instructions, it is advantageous to use firmware. "Firmware" is a group of program routines which are composed of ordinary instructions for performing the functions of such special instructions.
The inventors have previously attempted to construct a firmware area in the main memory in addition to the usual operating system area.
When such a construction is applied to a multi-processor system, it is necessary to form a plurality of prefix areas for the CPU's and, at the same time, a plurality of firmware areas for the CPU's. That is, each CPU must occupy both prefix and firmware areas in the main memory. There is, however, a problem with the above-mentioned construction, especially in a multiprocessor system. The function of the firmware is limited to some extent. Since firmware areas are allotted to all the CPU's independently, a sufficient amount of the program routines cannot be shared by each CPU due to the limited memory size of the main memory.